Recoil mechanism for a mortar



Apn'l 30, 1957 E. GARRETT RECOIL MECHANISM FOR A MORTAR Filed Sept. 16I 1952 April 30, 1957 E. GARRETT RECOIL MECHANISM F OR MORTAR 3 Sheets-Sheet 3 Filed Sept. 16, 1952 iuwmnm Unite States Patent RECHJ MECHANISM VFOR MORTAR Emil Garrett, Mauk, Ga.

Application Septemberr16, 1952, Serial No. 309,959

1 Claim. (Claw-d3) (Granted under Title 35, Code (1952,), sec. 266) The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment to me of any royalty thereon.

This invention relates to mortars.

An object of the inventionl is to provide a light weight al1-purpose mortar which can be continuously trained on a moving target.

Another object of the invention is to combine a mortar and mount which will enable the mortar to be'flred from a vehicle or from the ground.

Another object of the invention is to provide a mortarV which can be fired at a substantial range of angles of elevation beginning at zero or point blank elevation.

A further obj ect of the invention is to combine a mortar and mount which can be quickly assembled and levelled.

A further object of the invention is to providea mortar which can be quickly, easily andaccurately moved in azimuth and elevation.

A still further object of the invention is `to provide a mortar having a recoil mechanism which is particularly elective when combined with large caliber barrelsand a light weight mount.

Other objects and advantages will bevapparent from the following detailed description and the accompanying drawings, in which: i

Figure l is a longitudinal sectional view of the mortar attached to armachine gun type mount.

Figure Zvis a top plan view Of-thevmortar shown in Figure 1.

Figure 3 is a horizontal longitudinal sectional view of a mortar barrel and the recoil mechanism herein'disclosed.

Figure 4 is a transverse sectional viewon the line 4-4 of Figure 3. W

Figure 5 is an enlargeddetail view of a back plate used for connecting the recoil mechanism vto the mortar barrel.

Figure 6 is a modied form ofthe invention applied to a different type of mount.

lFigure 7 is ail top plan ofthe invention shown'in Figure 6.

Figure 8 is a vertical sectional view of-the barrel support on the line S--S of Figure 7, showingtthe'mu'nting of a recoil cylinder therein.

1 Figure 9 is a transverse sectional View on the line- 9 9 of Figure 8, and

vFigure 10 is a detailsectional view :of a. recoil cylinder having a tapered. bore at its.forward end.

The present inventionwasgdevised to provide a, mortar and mount which maybe Aquickly :set up .on lany typesurface. -By mounting it on avehicle it Abecomes., a highly mobile weapon 4capable. of,.ringvantpersonnel',or antitank projectiles.

.The ,normally retracted tiring means .insures .safe vmuzzle loading .with the barreleleyated end makes' possible tiring .-at zero elevation Gr.pression.

In ,the drawings,whereinfor the. purposegof illustra- Vtionis .shown acommon- .form,of.ftripod cmonntfA. It

ice

2 willbe understood, however, that any type of mount having means for adjustment in trainor elevatioi1`,""s'u"ch asthe mountV B, shown in Figure 6 may be used.

Referring now to Figures l through 5 the mount A has a rotatable pedestal 1 at its forward end, provided with a trunnion bearing 2. An elevating mechanism 3 located rearwardly of the Apedestal 1 is connected near thei'rear end of a barrel support 4. Near its forward end the barrel support carries a lug 5. A trunnion pin 6 passes through openings in the lug 5 and bearings 2 to provide pivotal movement for the barrel support 4.

The. barrel support 4 has a central bore-7 for lslidably receiving a lbarrel 8. A portion of the upper part of the barrel support is removed t'o'reducefriction, 1eaving' the remaining strap portions '9 to reinforce Vthe support. Flanges 10 are secured to or formed integrally with the barrel support 4 to extend along opposite sides thereof and on their outer edges carry recoil mechanisms 11, to be hereinafter more fully described.`

It is to be understood that the barrel support shown and described is only illustrative, and that differences in shape and construction may be resorted to, to provide for different types of mortar barrels and the demands of manufacture.

`The recoil mechanisms 11 are identical so that a description of one Will' suffice for both. i

Each recoil mechanism is housed in a hollow cylinder 12 containing a hydraulic uid. Fluid tight glands'13`are screw threaded on the ends of cylinder. Each cylinder is rigidly secured to the outer edge of its respective lange 1Q as by a weld 14.

An elongated piston rod 15 is axially disposed in each cylinder i2 and passes through central apertures in each of the glands 13, for guided axial translationl A piston 16 of slightly less diameter than'the bore of hollow cylinder 12, is secured to the piston rod 15 and thusforms a by-pass for the hydraulic fluid on recoil and counterrecoil movement of the mortar barrel.

Concentrically housed within each cylinder 12 is a helical compression spring 17, having its rear end bearing against the rear gland 13 and its front end bearing again-st the piston 16 to thereby urge rods 15 into forward or battery position. The spring 17 thus actsasl a recuperator after the forces of recoil have subsided.

The by-pass formed by the circumferential space betweenth-e piston and the inside wall of the cylinder provides a circumferential metering orifice to control the ow of hydraulic fluid on recoil and counterrecoil strokes of the mortar. i

Therbreech end of barrel 8 is screw threaded at 18 to receive a similarly yscrew threaded portion of a breech cap 19. The breech cap 19 has a reduced rearwardly extending projection 2@ terminating in a bulbous or spherical part, and concentrically located on its rear face. The projection 20 has a'bore 2i within which fits a firing pin Z2 which has an enlargement 23 slidable in a counterbore 24. A compression spring-2`5 is seated in the counterbore and bears againstthe enlargement 23 on the tiring pin 22 and serves to hold the tiring pin normally retracted. Screw-threadedly received in the rear end of the projectionZtl is a stop plug 26. The, stop plug is bored as at 27 to form a guide for the projecting rear end of the ring pin,'and counterbored as at 28 to form a stop for the enlargement 23 on the tiring pin.

Positioned transversely of ,th-e mortar at its rear end is aback plate 29 which, has a central opening 30 embracing the projection 20 on the breech cap 19. The back plate is of a length Vto Aoverlie the rear ends, of both recoil mechanisms and hasholes 31. aligned With and receiving Vthe rean ends of piston rods V15. .The rear ends` of ,theipiston ,rods arezs'c'rewthreaded ,andV nuts` y32 are threadedtthe'reon. .iAlreinforcing weby SalisA formed near the lower edge of the back plate and a similar web 34 is formed at its upper edge.

Spaced fingers integral with the web 3d extend rearwardlyand terminate in lugs 36 having aligned holes to receive a pin 39.

A firing pin actuator 37 includes a lever 38 .pivotally supported on pin 39 intermediate its ends. A weighted striker is fixed to lower end of lever 3S, and a leaf spring 41 is secured at one end to the fingers 35 and has its free end in contact with the lever 38 to normally urge the same counterclocltwise as seen in `Figure l and thereby hold the striker out of contact with the firing pin. A lanyard 42 is attached to the upper end of the lever 3S to provide the necessary force to drive the firing pin into firing position against the action of spring 25.

The simplicity of construction and ease of operation will be readily apparent to those skilled in the art and it is believed that a further description of the operation is unnecessary.

Referring now to Figures 6 through l() similar parts are designated by the same reference characters with the addition of the suffix a.

Figures 6 through l0 show a modified form of the invention, wherein a different barrel support and mount are used, but it is to be understood that other forms may be resorted to, as battle conditions require.

A pedestal 1a is rotatable about a pivot element E, affixed to the mount B, and terminates in a trunnion bearing 2a. An elevating mechanism 3a of modified form Wil-l hereinafter be more fully described.

A barrel support 4a, of lesser length than the support 4 shown in Figures l and 2, is provided. The barrel support 4a has a central bore 7a for slidably receiving a barrel 8a. Oppositely extending arms otr fianges Mia are rigid with the barrel support 4a and carry recoil mechanisms 11a, to be hereinafter more fully described.

At their outer ends, the arms or flanges ida carry U-shaped brackets d5, which are secured to the arms 10a by pins 46. The brackets d5 are formed with integral .forwardly extending lugs 5a, which have openings in alignment with the openings in the trunnion bearings 2a. Pins 6a pass through openings in the lugs 5a and the trunnion bearings 2a to permit elevation and depression of the barrel Sa.

The elevating mechanism comprises a standard 47 integral with one U-shaped bracket and has a swivel block 48 pivoted therein by pins 49. An elongated screw threaded rod is held in the swivel block 48 for rotation only. The rear end of the rod 50 extends beyond the swivel block and is provided with a hand wheel 51 for rotating the rod. The forward end of the rod passes `through a screw threaded hole in -a swivel block 52. The block 52 is pivotally supported by a pivot pin 53 to an off-set arm 54 which is secured to, or made integral with the pedestal la.

The recoil mechanisms 11a are identical so that a description of one will suffice.

Each of these recoil mechanisms includes a cylinder 12a containing a hydraulic fiuid. Fluid tight glands 13a are screw threaded in the ends of cylinder 12a. Each cylinder 12a is screw threadedly connected as at 55 in a bore 56 in its respective arm 10a, see Figure 8.

An elongated piston rod 15a is axial-ly disposed in each cylinder 12a 4and is supported and guided by the front and rear glands 13a. At the forward end of each cylinder the bore is flared outwardly as at 57 for a substantial distance. A piston ida of slightly less diameter than the bore of the cylinder, is secured to the rod 15a `and thus forms a by-pass which throttles the iiow of fiuid therepast on recoil movement of the barrel.

Concentr-ically housed within each cylinder 12a is a helical compression spring 17a, having its'rear end bearing against the rear Igland 13a and its 4front end bearing against the piston 16e. The spring 17a acts as a recuperator after the for-ccs of recoil have subsided.

The by-pass formed by the circumferential space between the piston and the inside wall of the cylinder provides a circumferential metering orice to control the flow of hydraulic fiuid on recoil and counter-recoil strokes of the mortar.

The barrel 3a is screw-threaded at 13a (Figure 8) to receive a similarly screw threaded portion of a breech cap 19a. The breech cap 19a has a reduced rearwardly extending projection 2da coaxially located on its rear face. The projection 29a has a bore 21a receiving a riring pin 22a which has an enlargement 23a slidable in a counterbore 24a. A compression spring 25a is seated in the counterbore and bears against the enlargement 23a on the firing pin 22a and serves to hold the firing pin normally retracted. Screw threadedly secured to the rear end of the projection 2da is a cap 26a. The cap is bored as at 27a to form a guide for the projecting rear end of the firing pin.

The breech cap 19a has oppositely extending arms 29u which performs the function of the back plate 29 in Figures l to 5. Each arm has a hole 31a for receiving the rear end of a piston rod 15a.

A finger 35a extends from the stop cap 25a and carries a pivot pin 39a for a lever 38a. At one end the lever 38a has a striker 40a and at its opposite end a lanyard 42a is attached. A safety device in this form of the invention, shown as a withdrawable pin 41a prevents `accidental operation of the firing means.

A handle 57 is carried by the U-shaped bracket 45 adjacent vthe elevation mechanism 3a 4for moving the mortar in azimuth.

Operation of both forms of the present invention is simply and quickly accomplished. Since the operation of the recoil mechanism is similar irrespective of the type of pedestal support used, the sequence of operation will be described with respect to the modification illustrated by Figures l and 3. In loading the shell into the gun tube, the elevating mechanism 3 is first lifted off the crossbar of mount A, then the gun barrel and recoil mechanism are lowered to the dotted line position illus- 'trated in Figure l. The shell is dropped into the gun tube in the conventional manner, however since firing pin 22 is withdrawn, the shell will not fire. The gun tube is now elevated to the solid-line position delineated in Figure 1, and is ready for, aiming and firing at a designated target. Firing is initiated by a pull on lanyard 42. As the shell is fired gun barrel 8 moves rearwardly on recoil. Rods 15 and pistons 16 are formed rearwardly compressing counterrecoil spring 17 and forcing recoil oil to the front of pistons 16 by Way of the annular clearance provided between the pistons and cylinders 12. The combined function of the oil and counterrecoil spring buffers the recoil forces to prevent jarring of the weapon as it arrives at maximum recoil position. At the end of the recoil stroke, spring 17 reacts to drive the gun barrel forwardly in counterrecoil to return the gun to battery position, with the metering orifice provided by the before-mentioned clearance again slowing the gun down at maximum counterrecoil to vitate the effect of the jarring forces when the gun arrives at the battery position.

It is to be understood that the forms of the invention, herewith shown and described, are to be taken as preferred examples of the same, and that various changes in the shape, size and arrangement of parts may be resorted to, without departing from the spirit of the invention, or the scope of the subjoned claim.

Having now fully disclosed the invention, what I claim and desire to secure by Letters Patent is:

In a recoil mechanism for a mortar, comprising a gun barrel having a closed breech with a central rearwardly extending projection, a tubular barrel support, a pair of spaced parallel fianges secured at one of their ends to diametrically opposite sides of said barrel support, a recoil cylinder secured to the other ends of each said pair of spaced arms and in parallelism with said gun barrel, means forming a fluid tight seal engaging the ends of each of said recoil cylinders, each of said cylinders receiving a recoil uid, an elongated piston rod axially reciprocable in each said recoil cylinder and extending through central apertures in each said sealing means, a piston integral with each said piston rod and providing a predetermined circumferential clearance between its outer face and the inner surface of its respective recoil cylinder, each of said circumferential clearances providing a metering orice to control the ow of recoil lluid past its respective piston when said barrel moves in recoil and counterrecoil eaoh of said pistons being positioned in the forward end of respective cylinders when said barrel is in battery position, a helical spring surrounding each piston rod and being confined between the rearward face of each piston and the rear sealing means, a back plate having a central aperture through which the rear- Ward projection on the barrel passes and extending transversely of said barrel beyond the rear ends of said piston rods, and means for securing the rear end of each piston rod to an adjacent end of said back plate.

References Cited in the le of this patent UNITED STATES PATENTS 1,288,372 Bell Dec. 17, 1918 1,411,627 Honsberg Apr. 4, 1922 1,754,943 Hammar Apr. l5, 1930 1,922,080 Driggs Aug. 15, 1933 2,030,507 Drigg-s Feb. 11, 1936 2,395,488 Lucht Feb. 26, 1946 2,442,371 Meyers et al. June 1, 1948 2,575,805 Glassey Nov. 20, 1951 FOREIGN PATENTS 100,016 Great Britain Ian. 8, 1916 

